Unfortunately I don't think there's going to be an easy answer for this particular camera, and I can't test the processes that various people have suggested.
My first suggestion would be to download
MPEG Streamclip (free) and see if that will recognise/play the video files you are trying to import. If it does, then you can use it to convert them to DV files that you can import into iMovie. Also,
VLC (also free) has a transcode option which should do a similar thing, and it recognises a huge number of formats.
Worst case would be to export to the MiniDVD and then use the tools above to convert to a format that iMovie can import. The problem there is that the MiniDVD won't work with Mac slot-type DVD drives unless you have an adaptor of some sort.
The Hitachi DZHS300a makes the whole process harder than it should be, but it is possible.
Let me know how you go.
PS. jmyers Quicktime Pro option might work too, but the options above don't require you to spend any money to find out.